Upwelling, Downwelling, Currents and El Nino

State Standards: GLEs/GSEs

ESS1 (Ext.)-3 Students demonstrate an understanding of processes and change over time within earth systems by
3aa describe how interactions of wind patterns, ocean currents, and mountain ranges results in the global pattern of latitudinal bands of rain forests and deserts.

National Standards:

Energy in Earth System 12DESS1.3 Heating of earth’s surface and atmosphere by the sun drives convection within the atmosphere and oceans, producing winds and ocean currents. 12DESS1.4 Global climate is determined by energy transfer from the sun at and near the earth’s surface. This energy transfer is influenced by dynamic processes such as cloud cover and the earth’s rotation, and static conditions such as the position of mountain ranges and oceans.

Context of Lesson:

Students will be introduced to the ocean and will apply the term convection zone to ocean currents. They will apply the idea of sun heating the earth's atmosphere to shown how El Nino like events can take place on earth.

Opportunities to Learn:

Depth of Knowledge:

Prerequisite Knowledge

Students should be familiar with a convection zone and how it relates to the atmospheres.

Plans for Differentiating Instruction:

Students who work well together with other students will benefit from group work. Visual learners will be targeted during group work using the globe and seeing visual explanations by their peers in front of the class.

Accommodations and Modifications

Class will accommodate diverse learners by making sure each student understands their topic before moving on to present their topic. Also, students will get the opportunity to teach each other if they do not understand one another.

Environmental Factors

Materials

handout of el nino (website found in lesson)
globe
Darwin finches slides from webCT
lego man
reader response
handout pg 251 fig 11.11 EarthComm

Objectives:

You will be able to:

Explain what it was that the fishermen were observing off the coasts of Peru
Identify a main ocean current and what drives it
Identify upwelling and downwelling
Offer an explanation for their observations
Describe how El Nino originates

Instruction:

Opening:

Quesiton 1 posed: What is the human population?
- Expected answer: 6.7 billion
  - http://www.census.gov/main/www/popclock.html is a good website to check this out at
Create a table, filling in human population 6.7 first, then 2.5 and have students guess if this is true

year
human population	2.5 billion	6.7 billion
global fish catch million tons/year	20	85

Don't fill in last row of table yet
Describe that during 1950s through 2002 there was an over exploitation of the marine fishery (now fill in 1950 and 2002 and the global fish catch)
Question 2 posed: What does this table shows us about population
- Expected answer: (it increased), so over exploitation was probably caused due to increase in population

Engagement:

Activity 1: Discovering Upwelling, Downdwelling and the fishing industry of the South Pacific Coast

COD was one of main fishes that hasn't recovered from the over-exploitation, we even shut down factories along E coast from 1994 through 1998 and fish still hasn't recovered... considered a very complicated problem
it is a problem for New Englanders just as it is for Peruvians
Good fishing industry of the coast of Peru and Ecuador, as well as Oregon/California (have student find Peru on the globe).
Question 1 posed: Why are the oceans and marine fisheries being introduced?
- Trigger prior knowledge: Have them think back to what happens with uneven heating of atmosphere, creates wind and hot air which rises and creates fantastic wind patterns across the entire globe.
- Explain that these patterns can also be observed in ocean too because it is another fluid system. It is these patterns affect marine life.
Question 2 posed: Can anyone remember what this cycle of hot air rising and falling is called?
- Expected Answer: Convection zones.
- The concept can now be applied to water movement.
Write on the board: Observing and analyzing ocean currents can help you realize the effect of wind patterns on the ocean.
There are surface currents (what we talked about, drives boats, surfing, how Christopher Columbus sailed over here) which are caused by the sun as we all know. But that is not the whole story... have hundreds of feet of water underneath you there is water moving below you as well. As wind creates friction against water, water creates friction against water beneath it. This creates little circles of rotation so water moves horizontally underneath a little bit too, just not as much as the top.
Does that make sense?
- Can someone think of an example where there are top layers that affect the bottom layers?
  - Expected answer: I would picture a 7-layered cake, with icing in the middle of each layer. If someone were to take the top layer and try to push it off the other 6 layers, the friction between the top and second layer would cause not just the top layer to move, but the 2nd, 3rd, 4th, and so on.
Create a diagram on the board of the following (use pg 250-251 The Blue Planet as a guide):
We are going to do a common sense activity. Picture the top 100 meters ocean are divided into, lets say, 3 layers of water.
- If wind is blowing parallel to the land, What will it do to the surface water (layer #1)?
  - Expected Answer: It fill pull the uppermost layers of water with it.
  - (Write question on board)
- What happens to the water directly underneath the surface water, layer #2?
  - Expected Answer: The surface water layer drags on the water immediately underneath it, setting that water in motion as well.
- What causes this movement:
  - Expected Answer: Friction.
- Will layer #2 move as fast as layer #3?
  - Expected Answer: No.
  - Why?
  - Because there is friction, the water underneath isn't exposed to the wind, so its only "push" is coming from the water, therefore it moves at a slightly slower speed.
- What will happen to layer #3?
  - Expected Asnwer: Slightly deeper, water will be pulled in that direction because of friction , but not as far.
- Everyone is doing great. Does this make sense so far?
  - Wait for questions and review if needed.
- What if I told you that all this is correct, but something else happens when we get deeper into the water. The water starts to move in a different direction. With each successive layer, it starts to move at a slightly different angle and by the time you reach 100 meters, the speed has dropped tremendously (no surprise) but the direction of the water has shifted 180 degrees so its going in a different direction than the wind!
- Can anyone give me a answer for this spinning? Hint: Think back to a couple classes that might have causes some other "fluid" to turn in different directions.
  - Expected Answer: Coriolis force actually veers the water in its path, and causes it to go towards the right
- We have just discovered the Ekman Spiral
  - Write Ekman Spiral above our numbered activity
- This spiral moves water, called...
  - Ekman transport: the average flow of surface water over the full depth of the spiral moves at about 90 degrees to the wind direction.
- But I just told you that it rotated 180 degrees, why is it only 90 degrees?
  - Expected answer: The spiral actually causes water to move in all different directions, but overall, the net flow of water through all the layers of surface water is in the direction 90 degrees from the wind.
- Encourage students to write this down in their notebook
- So if we go back to our main picture, when wind blows parallel to land, the Coriolis effect and the wind are actually contributing to this complex spiral in the surface waters
- If we are in the southern hemisphere, and wind is blowing North of the coast of Peru, which way is the water going to be pulled?
  - Expected answer: to the left, which would mean ekman transport pulls water away from the coast towards the ocean
  - What happens when water pulls away from the land? Is there just an empty void there?
    - Expected Answer: water from very botttom comes up to replace this escaping water = upwelling
- downdwelling, when water moves towards shore, surface water has no where to go but down underneath current and back out to sea
Have students draw a diagram in their notebook and write definitions next to them.
Explain that this movement creates a continuous cycle of rising/sinking water... that creates the currents underneath the ocean
Question 3 posed: What significance would upwelling and downdwelling have for the fishing industry?
- Allow students to brainstorm this idea of movement in the water. Without thinking of these two new vocabulary words, what would be beneficial for cycling of the water?
- Expected answer: With upwelling comes nutrients, which feeds fish populations which is why peruvians have good fishing industry there
Hand out figure 11.11 pg. 251 from book to illustrate hand out pg. 257 for reference)

Activity 2: Tying location to weather patterns

Ask students to think back to tradewinds we learned about (near equator). How would this effect Peru, which is near the coast?
- Expected answer: The winds on the equator exist near Peru. The great fishing industry is caused by the tradewinds.

Hand out this article El Nino article in Peru
Ask students if they would like it to be read aloud by someone, and then see if there is a volunteer or I will read it.
Allow twenty minutes for students to read
While they are reading, write the following on the board.
- Respond to the questions...
  - What do you think is the most important part of this article and why?
  - Do you think you can personally relate to anything in this article and why?
  - How does this relate to upwelling and why would we be discussing it in science class? (written on board and responded to)

Allow ten more minutes for discussion and to see if students can verbally relate it to the classdirect it towards upwelling and the disaster this might causewhy would this happen?
Introduce the trade winds once again and ask students if they remember them describe how they slacken upwelling reduced, fishing pop declines, birds die = local economic catastrophe sound familiar?? sounds like indonesia’s problem... the article I had you read
This is called El Nino

Activity 3: El Nino event formation

lets write a process because I’m throwing a lot of information at you
Have student jigsaw... separate into four groups (group will divide evenly (split your group in half, one half of your group will deal with new "hint" given by teacher, and other half will deal with notes you took in class) this is a small assessment of how useful your notes are to see if there is improvement
Students will be assigned tasks and will present their findings to the class in accordance to the following table:

Group #1	Where are the tradewinds located and where do trade winds come from?	Group #1 Hint	The sun heats the atmosphere [evenly/unevenly]. Some parts of the earth are closer to the sun than other parts. First, find the part of the earth that is closer than another part. Once the sun heats this area, the air becomes warm. Warm particles [rise/sink] and create an air flow. Can you remember why particles rise/sink compared to other ones? Remember, temperature of molecules are just a measure of the amount of energy the molecules have. The more energy they have, the more they have to move around, and the more space they take up... how would this affect the molecules, think back to what we did in the gym
Group #2	How does coriolis force affect trade winds?	Group #2 Hint	Tradewinds are the winds near the equator that travel horizontally across the earth in the West/East direction. Wind is not attached to the earth's crust. It acts like a fluid atmosphere over earth's surface. When the earth rotates, the Coriolis effect comes into play. Think back to why the winds would be affected by the rotation of the earth
Group #3	Which way to tradewinds usually flow?	Group #3 Hint	When you are looking from outer space at the top of the earth (looking down at the North Pole, the earth is rotating [clockwise/counterclockwise]. Use a globe to observe this. Make sure you rotate the globe the correct way. In order to do this, use an object to imitate the sun. The Sun always rises in the East. If you were the lego man on the globe, which way would the earth have to be spinning in order for you to see the rising sun in the east and the setting sun in the west? After you figure this out, then imagine a wind current flowing North/South. If the earth is rotating, which was will it "pull the current."
Group #4	If trade winds were to slow down, what would happen to the current of the atlantic ocean?	Group #4 Hint	This was just talked about in class today. Why does DEEPER water move in the atlantic ocean in the first place? We already know that the sun can create winds that affects the top layers of water, but the deeper layers of water create currents by convection zones. How would the cycle of a convection zone cycle warm and cold water together to create a continuous movement. If that source of movement goes away, would the currents of the Atlantic stop or continue?
Group #5	How would that affect the ecosystem of the atlantic?	Group #5 Hint	This is the reason fisheries die off in Peru. It involved nutrient loss because of upwelling. You must describe these two processes.

PERHAPS FIND (OVER BREAK) SOME ADDITIONAL SOURCES STUDENTS CAN USE TO DISCOVER THESE QUESTIONS WRITTEN ABOVE
Have students present their information to the class
Students of the class will help the group out if they are stuck... and as they are describing their reasons, I will write their answers on the board
Eventually after all groups have gone, students will realized that they had all the information they needed to figure out how an El Nino pattern forms
Focus on another example besides fisheries, and El Nino's impacts of it bird population declines
see webCT Evolution notes on Darwins Finches
Question 1 posed: Is anyone familiar with Darwins Finches?
- Pass out handouts of Darwins Finches slide that plots the number of finches during the drought

Closure:

Have students create a table to see the differences between an El Nino event and the absence of one.

describe normal conditions when El Nino is absent

El Nino conditions

Fill out this table together

Homework:

Describe what the graph of Darwin's Finches means. What does it deal with (hint is to look at the x and y axis to see what it is talking about). What does the data on the graph mean? What is the highest and lowest point on your graph. Was there a rise or decline in the number of finches? Why do you think this was the case. Have a hard copy to hand in for tomorrow's class.

Assessment:

The Closure and the student-taught lesson is a great formative assessment tool for me. I will talk with the students to see if this amount of information was to overwhelming and ask them to write down that they think is interesting, what they don't understand, and what they would like to know more about before leaving class.

Reflections:

(only done after lesson is enacted)
Student Work Sample 1: Approaching Proficiency
Student Work Sample 2: Proficient
Student Work Sample 3: Exceeds Proficiency

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